Heat exchanger for hot air furnaces



July 6, 1954 w. BUTLER ET AL HEAT EXCHANGER FOR HOT AIR FURNACES Filed May 25, 1950 Wendell But/er She/don F. Pride INVENTORS mf n09 5% Patented July 6, 19 54 HEAT EXCHANGER FOR HOT AIR FURNACES Wendell Butler and Sheldon F. Pride, Rupert, Idaho Application May 25, 1950, Serial No. 164,137

1 Claim.

This invention comprises novel and useful im-- provements in warm air furnaces, and more particularly pertains to improvements in warm air furnace heat exchangers.

An important object of this invention is to provide a heat exchanger for warm air types of furnaces, which heat exchanger is of simple construction, and which will more efficiently transfer the heat of the combustion gases to the air surrounding the heat exchanger.

An important feature of this invention resides in theprovision of a heat exchanger casing with a horizontally extending bafiie tube extending across the path of the combustion gases, which baiile tube directs the gases into contact with the casing, and which tube extends through one wall of the casing and conducts the gases therefrom.

Another important feature of this invention resides in the provision of a heat exchanger in accordance with the foregoing feature, which heat exchanger has a horizontal duct forming a radiator disposed about the casing in spaced relation thereto, and defining a passage therebetween, which radiator is in communication with the tubular baiile, on one side thereof, and which radiator is in communication with an exhaust conduiton the opposite side, whereby the combustion gases leaving the combustion chamber of the furnace contact a large heat radiating area.

These, together with various ancillary objects and features, are attained by this device, a preferred embodiment of which has been illustrated, by way of example only, in the accompanying drawings, wherein:

Figure 1 is a fragmentary top plan view of the with the combustion chamber, indicated general 1y by the numeral [2. The combustion chamber shown is constructed mainly for use with a low pressure fuel oil burner, but it is to be understood that a high pressure fuel oil burner, a natural or bottled gas burner, or other type of combustion chamber may be efficiently utilized with the heat exchanger, to be described more fully hereinafter;

The combustion chamber l2 shown in the drawings has substantially vertically extending side walls I 4 and a bottom wall [6, which side walls are lined with suitable fire brick [8, refractory cement 20 being provided on the bottom wall It. An aperture 2-2 is provided in the side walls [4 and in the fire brick I 8 and a fuel nozzle 2 3 extends through the aperture, in spaced relation to the sides of the aperture, so as to permit the introduction of air into the combustion chamber l2.

The heat exchanger [0 includes a casing having a horizontally disposed cylindrical dome 26 having end walls 28 and 30. It is intended that the side walls I4 of the combustion chamber l2 be cylindrically shaped, and of a diameter substantially equal to that of the dome 26, the extensions 32 on the side walls [4 being secured to the cylindrical dome 26, in any desired manner,

heat exchanger showing the radiator disposed about the periphery of the heat exchanger cas- 1n %igure 2 is a vertical sectional view taken substantially on the plane 2-2 of Figure 1, with arrows indicating the direction of the heated gases through the exchanger; and

Figure 3 is a transverse vertical sectional view taken substantially on the plane 33 of Figure 2, the arrows showing the manner in which the bafile tube directs the combustion gases into contact with the interior surfaces of the heat exchanger.

Referring now more specifically to the accom panying drawings, wherein like numerals designate similar parts throughout the various views, it will be seen that there is provided a heat exchanger, indicated generally by the numeral II], which is adapted to be mounted on or formed as by forming a conventional pipe fitters T. The dome 26 is apertured along the lines defined by the intersection of the two cylindrical bodies, the dome 26 and the extensions 32 of the combustion chamber l4, so that the dome is in communication with the combustion chamber.

A horizontally extending baflie tube 34 is positioned, preferably axially of the dome 26, which baflie tube terminates adjacent one of the end walls 28 of the dome 26, and extends through a bore 36 in the other end wall 30. It is intended that the free end 38 of the bailie tube 34, which terminates adjacent the end wall 28, be inclined so that the upper edge of the bafile tube terminates substantially farther away from the end wall 28 than does the lower edge, whereby the combustion gases impinging upon the lower side of the baflie tube will be directed to the periphery of the dome 26, the gases then circulating around, as indicated by the arrows shown in Figures 2 and 3, into the free end of the baffle tube, and out of the dome 26.

A duct forming a radiator 40 having a rectangular cross-section, as shown in Figures 2 and 3, is disposed about the periphery of the horizontally extending cylindrical dome 26, which radiator includes inner and outer walls 3 42 and 44, respectively, and upper and lower walls 46, the inner walls 42 being provided with an aperture 48 into which the externally extending end of the bafile tube 34 extends, so that the baffle tube is communicated with the radiator 40. An opposed side of the radiator 40 is provided with an aperture 50, upon which the sleeve 52 is secured, which sleeve receives the exhaust conduit 54 which conveys the exhaust gases toa suitable smoke stack or the like. It will thus be seen that the combustion gases, as they enter the cylindrical dome 26, are deflected by the tubular baiTle 34 so that they impinge upon the heat conducting side wall 26 of the dome, the

gases then circulating around the dome andleaving the casing by means of the free end 3-B- of the baffle tube, adjacent the upper. edge thereof, the combustion gases then being conducted by means of the radiator 40 aroundboth sides of the exterior of the dome 26, thereby heating a relatively large heat radiating surface before leaving through the exhaust conduit 54 From the foregoing, it is thought readily apparent that the bafile tube 34 will slow down the rate at which the heated gases or combustion gases leave the dome 26, whereby a more com plete combustion of the fuel is obtained and a more complete transfer of the heat from the gases to the dome is achieved.

Since it is believed that the operation and construction of the device will be readily understood from the foregoing description and accompanying drawings, further discussion is deemed unnecessary. However, since numerous modifications will readily occur to those skilled in the art after a consideration of the foregoing specification and accompanying drawings, it is not intended to limit the invention to that shown and described, but all suitable modifications may be resorted to falling within the scope of the appended claim.

Having described the claimed as new is:

A heat exchanger for furnaces comprising an elongated horizontally disposed cylindrical casinghaving, first and. second endwalls, a verti- Cally disposed housing communicating with the bottom of said casing intermediate the ends thereof and adapted to deliver combustion products thereto, anelongated tubular baffle tube extending axially of said casing, one end of said tube being disposed in close proximity to said first end wall, the other end of said tube extending through said second end wall, a continuous, horizontally extending combustion products duct of rectangular configuration spacedly surrounding said casing, said other end of said baffle tube opening into said combustion products duct, and an outlet conduit communicating with said duct adjacent said first end wall of said casing, said one end of said tube being vertically inclined invention, what is away from said first end wall to provide an upwardly opening entrance for combustion products from said casing.

References Cited in the file. of this patent UNITED STATES PATENTS Number Name Date 306,432 Rossman Oct. 14, 1884 480,086 Freeman Aug. 2, 1892 599,965 I-I'oifman Man 1, 1898 848,220 Albinson Mar. 26, 1907 973,879 Promenshenkel et a1 Oct. 25, 1910 2,227,449 Gillmor Jan. 7, 1941 

